1. Field of the Invention
The present invention relates to a color imaging system for use as an electronic still camera, for example.
2. Prior Art
Heretofore, the optical images of subjects are recorded using optical photographic cameras or combinations of television cameras and video tape recorders. It has also been customary to record audio information as well as image information on various recording mediums such as cinematographic films, magnetic video tapes, or the like.
Optical images recorded on photographic films with silver-salt light-sensitive photographic emulsions are of relatively high resolution, but can be reproduced only after being processed by the complex development process. Imaging devices such as television camera tubes produce video signals representative of optical images, and such produced video signals are typically recorded on magnetic video tapes by video tape recorders. While the recorded video images can quickly be reproduced, the reproduced video images are relatively low in resolution because the electron beams used in the television camera tubes are of limited diameter. Since the capacitance of the target in the camera tubes increases with the surface area of the target, the image resolution cannot be increased even if the target surface area is increased. Video signals indicative of moving images, which are produced by the television camera tubes, have frequencies ranging from several tens MHz to several hundreds MHz. These video signals will be poor in signal-to-noise ratio if the resolution is increased. Therefore, the television camera tubes cannot produce video signals of desired high quality and high resolution. Solid-state imaging devices for use in television cameras are also subject to limitations since it is difficult to two-dimensional solid-state sensors with as many pixels as required to achieve desired levels of image quality and resolution. Video tape recorders available on the market are not yet advanced enough to record and reproduce video signals in a wide frequency range for desired image quality and resolution.
There has recently been proposed an imaging system for recording images as highly fine electric charge images to make it possible to reproduce them with high quality and resolution. It has also been proposed to record electric charge images as representing video information such as still images and also electric charge images as representing audio information.
Such proposed imaging systems are disclosed in Japanese Patent Applications Nos. 61-311333, 62-226137, 62-305442, 63-122282, 63-289707, 1-89423, 1-189045, 1-291660, 1-319384, and Japanese Laid-Open Patent Publication No. 1-213619, for example.
However, the proposed imaging systems have not been satisfactory as they cannot easily be handled in practical applications.